Rick was already walking back up the hill toward the cornfield. "There's no other underground location in which a projector could be stored, is there? So let's get at it."

"Glad we brought flashlights," was Scotty's only comment.

They hiked in silence to the cornfield, pausing now and then among the corn plants to examine footprints. Thanks to the rain that had left the ground soft, there were plenty of them, but they told the boys no more than they already knew.

At the top of the hill above the mine they paused to survey the scene.

Belsely was hauling a load of rock through the field near the plane, using his tractor and a stoneboat. The boys knew he was busy building a stone fence. He saw them and waved. They waved back, then went down the hill to the spring and its basin.

Again they examined the entire location with great care, and Scotty probed seams in the rock with his jackknife blade. The entire hillside in this location was cracked and seamed and the rock face above the basin was rough and irregular. Rick wondered if there had ever been an earthquake in the neighborhood or whether the settling of the earth into the mine has caused the cracking.

"Nothing here," Scotty said. "At least nothing I can see. We'll have to try the mine itself."

They had replaced the boards at the entrance, simply pushing the nails back into the holes from which they had come. They pulled the boards aside and saw footprints--and not their own!

"Visitor," Scotty said with excitement.

Rick noted the size of the tracks. "And a big-footed one, too. Makes our tracks look small."

Scotty pointed. "He came out again, whoever he was. Let's see how far he went in."

The tracks told the story clearly and quickly. The visitor had gone in about twenty feet, and had then returned to the outside. One glance told the boys why.

The mine was timbered, with uprights and overhead beams s.p.a.ced about every ten feet. Where the visitor had stopped, the mine timbers were supporting a big piece--or many pieces--of the rock overhead. Rick guessed that the heavy rain, working through cracks, had loosened a section and let its weight fall on the overhead crosspiece. It was also clear that the timbers would not support the weight for very long. They were rotten, and wet with the constant seepage of water.

"Must have been one of the Sons of the Old Dominion who wandered in for a look," Rick suggested. "He saw it wasn't safe and went right out again."

"Something like that," Scotty agreed. "And it isn't safe. Those timbers would go if anyone breathed hard at them."

"Then let's not breathe hard," Rick said.

"Meaning that we're going in, anyway."

Rick pointed out, with what he thought was complete logic, that the timbers had held the roof up since the rain, and that collapse surely wouldn't take place in a minute or two. He concluded, "And if we're going to find any kind of clue to a projector, it has to be in this mine somewhere."

"Then let's not linger," Scotty said. "And for Pete's sake don't stamp your feet when you go by the timbers. A little vibration would send them down for sure."

Rick asked, "What were the wind and the laughter the last time we were in here?"

"Imagination," Scotty replied. "Let's keep it under control this time."

"I'm with you. And ghosts don't blow out flashlights, so let's go."

They moved cautiously past the unsafe place, lights probing the tunnel walls for a sign of anything unusual or worthy of attention. Now and then they reached a bay where ore had been taken out, or a jog in the tunnel where the miners had lost the ore vein temporarily. They reached the spot of their penetration into the mine on their last visit and found the remains of their torches.

"No change. Thought they might have been chewed by ghosts," Scotty commented.

"Newsprint doesn't taste good," Rick replied. "Do ghosts have teeth?"

"Nope, just an icy breath. Do you remember any smell, by the way? When we got hit in our faces?"

"Something sort of sweet?"

"Yes. I wasn't thinking about smelling, and I didn't notice especially, but I sort of recall a nice odor."

Rick thought he remembered it, too. "We'll look up methyl chloride in the dictionary," he promised. "That will tell us if it has an odor."

The mine took a sharp turn. "They lost the vein here and had to chew out some rock to find it again," Rick pointed out. "Notice everything is on one level? Must have been just one vein. It ran out and the mine closed down."

"Looks that way," Scotty agreed. "How far have we come?"

Rick hadn't kept track, but he estimated they were perhaps halfway under the hill. "This must end somewhere," he said. "Notice there isn't any water at all, not even seepage? I'm still baffled by that spring and the pipe."

They traversed another hundred yards in silence, flashlights constantly scanning the mine. There was nothing out of the ordinary, no sign of ghost, projector, or even of human visitation for dozens of years.

"We're on another wild-goose..." Rick began. He never finished, for sound suddenly reverberated through the mine, the sound of rock crashing downward.

Both boys turned and ran back toward the entrance, afraid of what they would find. Long before they reached it, billowing clouds of dust told them what had happened.

Their racing legs confirmed it as they came to a stop against rock that choked the tunnel from top to bottom.

[Ill.u.s.tration: _The timber had given way. They were trapped!_]

The timbers had given way. They were trapped!

CHAPTER XVII

In Darkness

For one despairing instant the two peered at the fallen rock through the thick haze of dust, then Scotty snapped, "Back into clean air."

They retreated the way they had come. Rick clicked off his flashlight instinctively. They might need it.

When clean air was reached again they stopped and Scotty swept his flashlight beam over the rocky floor. "Pick a seat and get comfortable.

We'll be here for a while."

"We won't get out of here by sitting down," Rick replied.

"No, and we won't do much until the dust settles, either. Relax and get cooled off. When the dust has settled a little, we can go back and see just how bad the block is."

Rick remembered the tons of rock above the timbers. The block had to be bad, he thought. There was plenty of rock there. Then, as he thought about it, he wasn't so sure. A pretty large area had shown cracks, but perhaps only a layer had fallen. They might be able to dig out. Nothing to do about it but wait and see.

Scotty switched off his light and the blackness closed in. Rick shifted uncomfortably. Once before he had been lost in complete blackness like this, in the Caves of Fear. But that had been different; he hadn't been exactly trapped in the same way then, and the caves had covered miles under a Tibetan mountain. At least he knew exactly where he was this time.

He said, "We should have brought a picnic lunch."